Valve detent mechanism

ABSTRACT

A solenoid-operated detent mechanism for a spool valve having a spring centered neutral position and a detented operating position. The mechanism includes a locking device in the form of a movable solenoid armature having a cam surface locking the detent balls in engagement with grooves in the spool in the detented position and releasable when energized to permit the spool centering spring to return the spool to neutral. One embodiment contemplates a longitudinally moving armature spring biased in one direction to urge detent balls radially into a spool detent groove and pulled oppositely by the solenoid upon actuation to release the balls. Another embodiment has a rotating armature that through a cam surface lifts radially spring-pressed detent pawls from the spool groove.

United States Patent 91 Pauls Feb. 5, 1974 [73] Assignee: The CessnaAircraft Company,

Wichita, Kans.

[22] Filed: July 15, 1971 [21] Appl. No.: 162,876

[52] US. Cl 251/297, 74/527, 91/358 A [51] Int. Cl. F16k 31/04 [58]Field of Search... 251/68, 297; 74/527; 91/392, 91/358 A [56] ReferencesCited I UNITED STATES PATENTS 3,420,393 1/1969 Omon .Q 91/358 A3,153,949 10/1964 Rice .L 74/527 2,632,821 3/1953 Wright et al; 74/527 X2,826,286 3/1958 Boyce 74/527 X 3,089,507 5/1963 Drake et al. 251/68 XPrimary ExaminerHenry T. Klinksiek Attorney, Agent, or Firm-Edward L.Brown, Jr.

[ ABSTRACT A solenoid-operated detent mechanism for a spool valve havinga spring centered neutral position and a detented operating position.The mechanism includes a locking device in the form of a movablesolenoid armature having a cam surface locking the detent balls inengagement with grooves in the spool in the detented position andreleasable when energized to permit the spool centering spring to returnthe spool to neutral. One embodiment contemplates a longitudinallymoving armature spring biased in one direction to urge detent ballsradially into a spool detent groove and pulled oppositely by thesolenoid upon actuation to release the balls. Another embodiment has arotating armature that through a cam surface lifts radiallyspring-pressed detent pawls from the spool groove.

6 Claims, 4 Drawing Figures PATENIEDFEB 19M 3.790;1.29

SHEEI 1 0F 2 INVENTOR ATTORNEY PATENIEBFEB 51914 3.790.129

' sum 2 or 2 F IG. 4

INVENTOR CHARL ES W. PAULS ORNEY VALVE DETENT MECHANISM BACKGROUND OFTHE INVENTION This invention relates to hydraulic spool control valveswith detent positions and relates more particularly to meansautomatically releasing the detent mechanism.

Spool type valves include generally a valve body having a longitudinalbore in which the control spool is reciprocable to control fluid flowthrough fluid passages in the body. A conventional application of suchvalve contem-plates flow control between a fluid pump and a pressureoperated mechanism such as a hydraulic cylinder. It is also well knownto provide such a valve with a spring centering mechanism engaging thespool and urging same to a neutral position blocking flow to the motorand a detent mechanism which holds or locks the spool in a secondmotor-actuating position against the bias of the centering spring.

SUMMARY OF THE INVENTION The-present invention contemplates improvedautomatic detentrelease means which upon actuation unlocks the detent topermit the centering spring to return the spool automatically to thefirst neutral position.

The invention includes radially moving detent members which move into acooperating groove in the spool upon shifting the spool to a secondposition remote from the first position to which the spool is springbiased. Another spring biases the detent means toward the spool grooveinto a locking position. Locking means engage the detent members througha cam surface and actuating means, when energized, displace the lockingmeans so as to relieve the spring bias on the detent members. Thereupon,the spool centering spring forces the detent mechanism out of itslocking position and returns the spool automatically to the firstposition. The preferred embodiments utilize an electric solenoid asactuating means whose circuit is closed and energized upon movement whenthe hydraulic motor associated with the valve moves to the end of itsstroke or to a predetermined position. The locking means are formed asan integral part of the solenoid plunger which is drawn against thedetent spring upon energization of the solenoid to permit the spool toreturn to neutral automatically and cease fluid flow to the motor. Oneembodiment incorporates a longitudinally moving plunger or armaturewhile another uses a rotary-action armature.

Accordingly, the invention broadly contemplates a detent mechanism withautomatic detent release means for unlocking the spool detent to permitthe spool centering means to return the spool to a non-detent position.

A more specific object of the present invention is to provide a radiallyacting detent means holding the spool in a detented position against thebias of spring means normally urging the spool to a neutral position,and a release mechanism automatically unlocking said detent means.

A furtherobject in accordance with the preceding contemplates anactuating solenoid whose armature forms the locking mechanism, thesolenoid energized to a releasing position in response toa-predetermined condition in the hydraulic system.

These and other specific objectives and advantages of the presentinvention will be found in the following detailed description of thepreferred embodiments and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representationof a hydraulic system incorporating the present invention with thecontrol valve and detent shown in longitudinal crosssection;

FIG. 2 is an enlarged cross-sectional view of the detent and releasemechanism of FIG. 1;

FIG. 3 is a cross-section similar to FIG. 2 showing another embodimentofthe invention; and

FIG. 4 is a transverse cross-section taken along line 4-4 of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring specificallyto the drawings in which like numerals refer to the same elementsthroughout the several views, FIG. 1 illustrates a hydraulic systemcomprising a fluid pump 10, fluid motor 11 shown as a linear cylinderand control valve 12 interposed between the pump and motor. Fluidconduits, illustrated schematically by double lines, interconnect thevalve with the pump, reservoir and opposite ends 14, 15 of the motor.

Control valve 12 has a body 16 with a longitudinal bore 17 andintersected by axially spaced passages 18-22. Outer passages 18 and 22provide return of low pressure fluid to the reservoir while passage 20carries pressure fluid to bore 17 from the pump. The work port passages19 and 21 respectively connect with the opposite cylinder ends 14, 15. Amanually shiftable spool 23 fits closely within bore 17 so as to isolateboth motor ports 19, 21 from the adjacent inlet and outlet passages whenthe spool is in the neutral position shown. Upon leftward movement awayfrom neutral, the reduced diameterspool groove at the right end of thespool permits connection of port 19 with inlet passage 20 and connectionof the other port 21 with return passage 22. Motive fluid delivered tomotor chamber 14 drives piston 24 leftwardly, and fluid displaced fromcylinder end 15 returns through passages 21 and 22 to reservoir.Rightward spool movement from neutral similarly drives the piston theopposite direction by connecting motor chamber 15 with the prssuresource and chamber 14 with the reservoir through passages 18 and 19. Itwill be understood that the foregoing valve construction and arrangementof passages is typical and that the detent described herein is adaptableto numerous valve construction.

A hollow cap 25 secured to the valve body covers the left end of spool23 and houses the spool centering spring 26, the detent 27 and detentrelease 28, all of which are described in greater detail below withreference to FIG. 2. Centering spring 26 biases spool 23 to the neutralposition in the absence of other forces on the spool, while the detent27 acts upon leftward movement of thespool to hold the spool unattendedin a position driving the motor piston 24 leftwardly.

A solenoid 29 mounted to cap 25 energizes the detent release 28 uponclosingof sensing switch 30 by.pis ton 24. In consequence, the releasemechanism 28 unlocks detent 27 to permit the centering spring 26 toreturn .the spool to neutral. The FIG. 1 system thus provides anautomatic sequence control of motor 11: the spool is shifted manually toits detent position driving the piston leftwardly; the spool is held inthis motoractuating position by the detent until the piston 24 reaches apredetermined position along the stroke actuating the switch completingthe circuit and energizing solenoid 29; thereupon, detent mechanism isreleased and the spool returns to a neutral position, blocking flow tothe motor and bringing the piston to rest at a predetermine position inthis case.

Referring now to FIG. 2 which shows spool 23 in a detented position, thestructure and operation of the invention are described in greaterdetail. In the detented position, spring 26 acts through the cup-shapedwashers between spool shoulder 32 and an internal flanged portion of cap25 to urge the spool rightwardly toward neutral. As seen in FIG. 1, whenthe spool is in its neutral position, the centering spring extendsbetween the valve body 16 and end cup 25. The left end of the spool isprovided with converging tapered land that define a reduced diametersection 33 in which a plurality of symmetrically disposed detent balls27 rest when the spool is in neutral.

The detent balls 27 move radially outwardly and then drop inwardly intothe spool groove 34 as the spool is shifted to the detent position.Detent spring 35 biases sleeve member 36 rightwardly so that itschamfered end 37 acts as a cam translating this linear spring force intoa radial component holding the balls 27 in groove 34.'This locks thespool in detented position as the bias of centering spring 31 isinsufficient to push the balls out of groove 34.

Sleeve 36 is an integral portion of the longitudinally movable plungeror armature of solenoid 29. The solenoid winding 38 encircles the solidcylindrical portion of armature or plunger 36 which has a blind bore 39which receives the spool end. Upon energizing the solenoid as abovedescribed, armature 36 becomes magnetized and the magnetic field in thesolenoid acting on the induced poles on. the plunger causes the plunger36 to move within the solenoid leftwardly against the bias of detentspring 35. Cam surface 37 leaves contact with balls 27 to relieve thebias of spring 35 from balls 27. This allows centering spring 26 to pullspool 23 rightwardly to a neutral position by displacing balls 27radially from groove 34.

It will be obvious that although I have shown the detent mechanism onlyin cooperation with one end of the valve, it is easily adaptable toeither or both ends of the spool to permit various detent positions.

The embodiment shown in FIGS. 3 and 4 differs from that shown in FIG. 1in that the release mechanism rotates and includes a plurality ofsymmetrically disposed pawls 40 in place of the ball detent. Each pawlis individually urged by a spring 41 inwardly against the spool 23. Thespool is shown in its neutral position. The pawls have reduced diameterinner ends that drop into groove 34 upon positioning the spool to itsdetent position.

The actuating solenoid 42 in FIG. 3 is of the rotary type powering itsarmature 43 to rotate about the longitudinal spool axis. The armaturehas a blind bore accepting spool 23 and, as shown in FIG. 4, amultilobed camming surface 44 engaging the pawl shoulders 45. The pawlinner ends extend through slots 46 in the armature to contact the spool.

Upon energizing solenoid 42, armature 43 rotates counterclockwise asseen in FIG. 4 causing portions 47 of cam surface 44 to engage shoulders45 to force pawls 40 outwardly compressing springs 41. The pawls arelifted out of groove 34, and centering spring 26 returns spool 23 toneutral. When the solenoid is deenergized, the springs 41, actingthrough shoulders 45 and cam surface 44, rotate armature 43 clockwiseback to its FIGS. 4 position.

The detent release mechanism of this invention, although electricallyactuated, may be manually released in case of power failure or otherelectrical malfunction. In such a case the operator may return the spoolto neutral by exerting sufficient manual force to cause the detent ballsto be urged outwardly against surface 37 due to the force applied andpermit disengagement and return of the spool to a neutral position.

The foregoing detailed description of the invention is to be consideredexemplary in nature and not as limiting the scope and spirit of theinvention as set forth in the appended claims.

Having described my invention with sufficient clarity that those skilledin the art may use and practice same, I claim:

1. A valve mechanism controlling flow between a fluid source and ahydraulic motor, comprising:

a valve body having a longitudinal bore, an inlet passage communicatingwith said source and an outlet passage communicating with the motor,saidpassages intersecting said bore at spaced locations;

a spool in said bore manually shiftable between a first positionblocking flow between said passages and a second position directingfluid from the inlet to the outlet passage through the bore, said spoolhaving an outer reduced diameter section, an adjacent annular groove anda tapered land section therebetween;

A first spring engaging the spool to urge same to the first position;

a detent mechanism radially registering with said annular groove in saidspool upon movement of the spool to the second position;

second spring means urging the detent mechanism into said annular grooveto hold the spool in said second position directing flow to the motor;

a solenoid at one end of said spool having a movable armature with ablind bore accepting the outer end of said spool and a cam surfaceengaging said detent mechanism, said solenoid when energized actuatingthe armature to relieve the bias of said second spring means on thedetent; and

means sensing movement of the motor to a predetermined position andthereupon energizing the solenoid to relieve the bias of said secondspring means and thereby permit said first spring means to return thespool to said first position blocking flow to the motor.

2. The device of claim 1 wherein said second spring means directlyengages said detent means to urge same radially into said spool grooveand said armature rotates upon energizing the solenoid to oppose thebiasing force of said second spring means and shift said locking meansto said release position.

3. The device of claim 1 wherein said detent'means are a plurality ofpistons having inner ends engaging the spool groove in said secondposition and wherein said armature has a sleeve surrounding the spool,an exterior cam surface engaging a portion of said pistons, saidsolenoid when energized rotating said sleeve to lift said pistons out ofthe spool groove and permit the first spring means to return the spoolto said first position.

4. The device of claim 4 wherein said second spring means acts throughsaid armature to bias the detent and wherein said armature shifts torelieve said second spring bias and permit said first spring means tourge said detent radially out of said groove and return the spool tosaid first position.

5. The device of claim 5 wherein said armature has an external camsurface engaging said detent and rotates upon actuation to lift saiddetent radially out of said groove, and wherein said second spring meansextends radially between said valve body and detent to urge the latterinwardly toward said groove.

6. In a hydraulic spool control valve comprising a body having alongitudinal bore and fluid carrying passages intersecting the bores, aspool shiftable in said bore between first and second positions tocontrol flow between said passages through said bore, and first springmeans engaging and biasing said spool to the first position, wherein theimprovement comprises:

said spool having an outer reduced diameter section and adjacent annulargroove and a tapered land section therebetween;

radially movable ball detent means which register with said groove uponpositioning the spool in said second position and which are accomodatedin said reduced diametral section when said spool is in said firstposition; I

a solenoid armature having a bore accepting the spool end and agenerally concave carn surface;

second spring means biasing said armature into engagement with saiddetent balls and holding said balls in register with said groove whensaid spool is in said second position; and

a solenoid cooperating with said armature, said solenoid when energizedcausing said armature to iongitudinally shift against the bias of thesecond spring thereby permitting said detent to radially eject from saidgroove permitting said first spring to return said spool to said firstposition.

1. A valve mechanism controlling flow between a fluid source and ahydraulic motor, comprising: a valve body having a longitudinal bore, aninlet passage communicating with said source and an outlet passagecommunicating with the motor,said passages intersecting said bore atspaced locations; a spool in said bore manually shiftable between afirst position blocking flow between said passages and a second positiondirecting fluid from the inlet to the outlet passage through the bore,said spool having an outer reduced diameter section, an adjacent annulargroove and a tapered land section therebetween; A first spring engagingthe spool to urge same to the first position; a detent mechanismradially registering with said annular groove in said spool uponmovement of the spool to the second position; second spring means urgingthe detent mechanism into said annular groove to hold the spool in saidsecond position directing flow to the motor; a solenoid at one end ofsaid spool having a movable armature with a blind bore accepting theouter end of said spool and a cam surface engaging said detentmechanism, said solenoid when energized actuating the armature torelieve the bias of said second spring means on the detent; and meanssensing movement of the motor to a predetermined position and thereuponenergizing the solenoid to relieve the bias of said second spring meansand thereby permit said first spring means to return the spool to saidfirst position blocking flow to the motor.
 2. The device of claim 1wherein said second spring means directly engages said detent means tourge same radially into said spool groove and said armature rotates uponenergizing the solenoid to oppose the biasing force of said secondspring means and shift said locking means to said release position. 3.The device of claim 1 wherein said detent means are a plurality ofpistons having inner ends engaging the spool groove in said secondposition and wherein said armature has a sleeve surrounding the spool,an exterior cam surface engaging a portion of said pistons, saidsolenoid when energized rotating said sleeve to lift said pistons out ofthe spool groove and permit the first spring means to return the spoolto said first position.
 4. The device of claim 4 wherein said secondspring means acts through said armature to bias the detent and whereinsaid armature shifts to relieve said second spring bias and permit saidfirst spring means to urge said detent radially out of said groove andreturn the spool to said first position.
 5. The device of claim 5wherein said armature has an external cam surface engaging said detentand rotates upon actuation to lift said detent radially out of saidgroove, and wherein said second spring means extends radially betweensaid valve body and detent to urge the latter inwardly toward saidgroove.
 6. In a hydraulic spool control valve comprising a body having alongitudinal bore and fluid carrying passages intersecting the bores, aspool shiftable in said bore between first and second positions tocontrol flow between said passages through said bore, and first springmeans engaging and biasing said spool to the first position, wherein theimprovement comprises: said spool having an outer reduced diametersection and adjacent annular groove and a tapered land sectiontherebetween; radially movable ball detent means which register withsaid groove upon positioning the spool in said second position and whichare accomodated in said reduced diametral section when said spool is insaid first position; a solenoid armature having a bore accepting thespool end and a generally concave cam surface; second spring meansbiasing said armature into engagement with said detent balls and holdingsaid balls in register with said groove when said spool is in saidsecond position; and a solenoid cooperating with said armature, saidsolenoid when energized causing said armature to longitudinally shiftagainst the bias of the second spring thereby permitting said detent toradially eject from said groove permitting said first spring to returnsaid spool to said first position.